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Home My WebLink AboutNATHAN'S SUBDIVISION, 637 COWAN STREET - PDP/FDP - FDP130030 - SUBMITTAL DOCUMENTS - ROUND 1 - RECOMMENDATION/REPORT-3 -2 -1 F- 1 2 3 4 5 6 0.1 1 10 STREW, kst Specimen Identification Classification I 7d MC°10 • 2 8.0 Lean Clay with Sand 116 6 CONSOLIDATION TEST Northern s 2Coionado 'sbee unft 21 Client Lamar Valley Craftsman Number. 012-03 - Colorado s' a Geotech � 9 4 Project Proposed Residence Location: 637 Cowan Street •3 .2 1 6 2 3 4 5 6 0.1 1 1 STRESS, ksr Specimen Identification Classification Y4 MC°k • 1 3.0 Lean Clay with Sand 103 7 Northern CONSOLIDATION TEST 2s6s'' urn 21 Client: Lamar Valley Craftsman Number. 012-03 . GeoteCh � 970'60&8242 Project Proposed Residence LOG OF BORING No. 2 Sheet 1 of 1 CLIENT ARCHITECT/ENGINEER Lamar Valley Craftsman SnE 637 Cowan Street PROJECT ` Fort Collins, Colorado Proposed Residence SAMPLES TESTS O 7R. _ , W X y W Z h 0 0 ~ LL E1 yKJ Z > W rn W Z 9L 0— Z_ LL 2 a = (j5 _j W IMP CU Or LU D ui Approx Surface Elev.: 100A fL o n a pj m i 2 zz a a ? ? 2 ,� O OL zO $ � ¢ a. M n- 6' TOPSOIL �� 21 1 SS 16 13 os 99.9 LEAN CLAY WITH SAND Brown to tan, dry, stiff to very stiff 9 2 SS 12 5 5 23 3 RS 12 6 118 8,000 1.1 % SINE ti 10 12.0 88.4 SILTY SAND WITH GRAVEL Tan, dry, dense 51 4 SS 12 4 15.0 85.4.15 BOTTOM OF BORING WATBtLEVEL OBSERVAT10Ns Northem COIOfadO STARTED 121/03 FvusHm 1/21/03 WL None W.D. GeOtech All,WL oRnL eo• Drilling Eng oRUJ RrG GME-55 None A.& 295E 2Mh Skeet Urd 21 LOGGED BY DBC APPRovED DML cr. caorado a0s31 Phone: 970506W" —Fax 970 606.9242• When Checked 2 Days A B. Rco PROAMT NO. 012-03 CLIENT SITE LOG OF BORING -No. 1 ARCHITECTIENGINEER Lamar Valley Craftsman 637 Cowan Street PROJECT Fort Collins. Colorado Pi rox. Surface Elev.: 1002 fL 0.5 6" TOPSOIL LEAN CLAY WITH SAND Brown to tan, dry, stiff to very stiff SILTY SAND WITH GRAVEL Tan, dry, dense WATER LEVEL OBSERVATIONS WL None W.D. wL None as. When Checked 2 Days A.B. Sheet 1 of 1 Residence SAMPLES TESTS LU 0 U) O U LL! ZW ZLL .~W f/10 >j W 't~ (L W U -, U 2 a O� m f W KW oo y 0 >.W Og z0 OFW ENOz aq O Wz 2 Oa vHMaC i a '• a 16 1 SS 18 14 /►vW1U►cn► Colorado Geotech 29W 29M Saeer, Urt 21 Greeley. Cd wado $0631 Phone:, 970406-8244 18 1 2 1 RS 1 12 1 7 1 103 20 13 I SS I 12 19 a 32 1 4 1 SS 1 12 1 6 0.6% SWEL STARTED 121/03 Fms m 1/21/03 oRaLco. Drilling Eng DmLRw CME-55 LOGGED BY DBC APPROVED DML NW PROJECT No. 012-03 EXISTING RESIDENCE TBM ■ TOP OF THE CONCRETE STEP (EAST SIDE) FOR EIOSTING RESIDENCE B". ■ 100.0 D8 2 EXISTING I SHED �4,1 PROPOSED RESIDENCE No. 2 BORING LOCATION PLAN N PROPOSED RESIDENCE W COWAN STREET 3 FCRT COLLINS. COLORADO , FOR LAMAR VALLEY CRAFTSMAN Nodhem P*dt ' 012a3 Colorado eNk 1•.w Geotech Drr 241-05 2M 20 ShK Un t 21 Pfd6W DML F■C Q= "Nm i Lamar Valley Craftsman 637 Cowan Street Northern Colorado Geotech Project No. 012-03 Imported soils (if required) should conform to the following: Percent fines by weight Gradation (ASTM C136) 6".........................................................................................................100 3"....................................................................................................70-100 No. 4 Sieve.....................................................................................50-100 No. 200 Sieve..............................................................................60 (max) r • Liquid Limit.......................................................................30 (max) Plasticity Index.................................................................15 (max) Material Minimum Percent (ASTM D698) Scarified subgrade soils.........................................................................95 On -site and imported fill soils: Beneath foundations..................................................................95 Beneathslabs............................................................................ 95 On -site or imported day soils should. be compacted within a moisture content.range of 2 percent below, to 2 percent above optimum. Granular soils should be compacted within a moisture range of 3 percent below to 3 percent above optimum unless modified by the project geotechnical engineer. GENERAL COMMENTS The analysis and recommendations presented in this report are based upon data obtained from borings performed to obtain representative subsurface conditions at the site. Variations in the soil between borings will occur. Northern Colorado Geotech should be present during construction to observe the excavation and construction procedures and confirm or modify our recommendations. The scope of services for this project does not include either -specifically or by implication any environmental assessment of the site. This report has been prepared in accordance with generally accepted geotechnical engineering practices in this area at this time. No warranties, either express or implied, are intended or made. E1 Lamar Valley Craftsman 637 Cowan Street Northern Colorado Geotech Project No. 012-03 engineered fill, subgrade preparation, foundation bearing soils, and other geotechnical conditions exposed during the construction of the project. Site Preparation Strip and remove existing vegetation, debris, and other deleterious materials from proposed building and pavement areas. All exposed surfaces should be free of mounds and depressions which could prevent uniform compaction. Stripped materials consisting of vegetation and organic materials should be wasted from the site, or used to revegetate landscaped areas or exposed slopes after completion of grading operations. If unexpected fills or underground facilities are encountered, such features should be removed and the excavation thoroughly cleaned prior to backfill placement and/or construction. It is anticipated that excavations for the proposed construction can be accomplished with conventional earthmoving equipment The individual contractor(s) is responsible for designing and constructing stable, temporary excavations as required to maintain stability of both the excavation sides and bottom. All excavations should be.sloped or shored in the interest of safety following local, and federal regulations, including current OSHA excavation and trench safety standards. Fill Materials and Placement All exposed areas which will receive fill should be scarified to a minimum depth of eight inches, conditioned to near optimum moisture content, and compacted. The placement of soils on the site should be observed by Northern Colorado Geotech. The fill should be assessed for suitability of use in the proposed fill and tested for placement including compaction percentage and moisture content. Engineered fill should be placed and compacted in horizontal lifts, using equipment and procedures that will produce recommended moisture contents and densities throughout the lift. Recommended compaction criteria for engineered fill materials are as follows: Clean on -site soils or approved imported materials may be used as fill material. 7 Lamar Valley Craftsman 637 Cowan Street Northern Colorado Geotech Project No. 012-03 Additional floor slab design and construction recommendations are as follows: • Positive separations and/or isolation joints should be provided between slabs and all foundations, columns or utility lines to allow independent movement. • Control joints should be provided in slabs to control the location and extent of cracking. • Interior trench backfill placed beneath slabs should be compacted in accordance with recommended specifications outlined below. • A minimum 24nch void space should be constructed. above, or below non -bearing partition walls placed on the floor slab. Special framing details should be provided at door jambs and frames within partition walls to avoid potential distortion. Partition walls should be isolated from suspended ceilings. • In areas subjected to normal loading, a minimum flinch layer of sand, dean -graded gravel or aggregate base course should be placed beneath interior slabs. • A minimum flinch layer of free -draining gravel should be placed beneath basement floor slabs in conjunction with the underslab drainage system. • Floor slabs should not be constructed on frozen subgrade. Exterior slabs -on -grade, exterior architectural features, and utilities founded on, or in backfill may experience some movement due to the volume change of the backfill. Potential movement could be reduced by: • minimizing moisture increases in the backfill • controlling moisture -density during placement of backfill using designs which allow vertical movement between the exterior features and adjoining structural elements • placing effective control joints on relatively dose centers General Earthwork All earthwork on the project should be observed and evaluated by Northern Colorado Geotech. The evaluation of earthwork should include observation and testing of 2 Lamar Valley Craftsman 637 Cowan Street Northern Colorado Geoteeh Project No. 012-03 Perched groundwater may occur at times since the subsurface soils are relatively impermeable and tend to trap water. Completion of site development, including installation of landscaping and irrigation systems, may lead to perched groundwater development To reduce the potential for groundwater to impact foundation bearing soils and enter the basement of the structure, installation of a perimeter drainage system is recommended. The drainage system should be Constructed around the exterior perimeter of the basement foundation, and sloped at a minimum 1/8 inch per foot to a suitable outlet, such as a sump and pump system. The drainage system should consist of a properly sized perforated pipe, embedded in free -draining gravel, placed in a trench at least 12 inches in width_ Gravel should extend a minimum of 3 inches beneath the bottom of the pipe, and at least 2 feet above the bottom of the foundation wall. The gravel should be covered with drainage fabric prior to placement of foundation backfill. Surface Drainage Positive drainage should be provided during construction and maintained throughout the life of the proposed project. Infiltration of water into utility or foundation excavations must be prevented during construction. Planters and other surface features which could retain water in areas adjacent to the building or pavements should be sealed or eliminated. In areas where sidewalks or paving do not immediately adjoin the structure, we recommend that protective slopes be provided with a minimum grade of approximately 10 percent for at least 10 feet from perimeter walls. Backfill against footings, exterior walls, and in utility and sprinkler line trenches should be well compacted and free of all construction debris to reduce the possibility of moisture infiltration. Downspouts, roof drains or scuppers should discharge into splash blocks or extensions when the ground surface beneath such features is not protected by exterior slabs or paving.' Sprinkler systems should not be installed within 5 feet of foundation walls. Landscaped irrigation adjacent to the foundation system should be minimized or eliminated. Floor Slab Design and Construction Due to the expansive potential of the clay soils at approximate slab subgrade elevation, differential slab movement on the order of 1 inch or more is possible should expansive soils become elevated in moisture content A common practice to reduce potential slab heave involves overexcavation of the expansive soils and replacing these materials with non -expansive imported fill. This alternative Will not eliminate the possibility of slab heave; but movements should be reduced and tend to be more uniform. 5 Lamar Valley Craftsman 637 Cowan Street Northern Colorado Geotech Project No. 012-03 Design and construction recommendations for foundation systems and other earth connected phases of the project are outlined below. Footing Foundations Based on the results of our subsurface exploration and laboratory testing, it is our opinion that a spread footing foundation system bearing upon undisturbed soil and/or engineered fill may be used for support of the proposed structure. The footings may be designed for a maximum bearing pressure of 2,000 psf. In addition, the footings should be sized to maintain a minimum dead -load pressure of 500 psf. The design bearing pressure applies to dead loads plus design live load conditions. The design bearing pressure may be increased by one-third when considering total loads that include wind or seismic conditions. Exterior footings should be placed a minimum of 30 inches below finished grade for frost protection and to provide Confinement for the bearing soils. Finished grade is the lowest adjacent grade for perimeter footings. Footings should be proportioned to reduce differential foundation movement. Proportioning on the basis of equal total settlement is recommended; however, proportioning to relative constant dead - load pressure will also reduce differential settlement between adjacent footings. Total settlement resulting from the assumed structural loads is estimated to be on the order of 3/4 inch or less. Differential settlement should be on the order of 1/2 ' to 3/4 of the estimated total 'settlement. Additional foundation movements could occur if water from any source infiltrates the.foundation soils; therefore, proper drainage should be provided in the final design and during construction. Foundations and masonry walls should be reinforced as necessary to reduce the potential for distress caused by differential foundation movement The use of joints at openings or other discontinuities in masonry walls is recommended. Foundation excavations should be observed by Northern Colorado Geotech. If the soil conditions encountered differ significantly from those presented in this report, supplemental recommendations may be required. Below Grade Construction Groundwater was not encountered on the site to the maximum depth of exploration, 15 feet. Therefore, full -depth basement construction is considered acceptable on the site. 4 Lamar Valley Craftsman 637 Cowan Street Northern Colorado Geotech Project No. 012-03 Water Content • Compressive Strength Dry Density Expansion • Consolidation SUBSURFACE CONDITIONS Soil Conditions Soils at the site generally consisted of lean day with sand to depths of approximately 12 feet The materials underlying the surface soils and extending to the maximum depth of exploration consisted of silty sand with gravel. Summary boring logs are attached with this report . Groundwater Conditions Groundwater was not observed in any test boring at the time of field exploration, nor when checked two days after the drilling. These observations represent groundwater conditions at the time of the field exploration, and may not be indicative of other times, or at other locations. Groundwater conditions canbe expected to fluctuate with varying seasonal and weather conditions, and other factors. Field Test Results Field test results indicate that the day soils vary from stiff to very stiff in consistency. The sand soils are dense in relative density. Laboratory Test Results Laboratory test results indicate that the day soils have low expansive potential and low to moderate load bearing capabilities. DESIGN RECOMMENDATIONS Foundation Design Based on the results of our subsurface exploration and the results of the laboratory testing, it is our opinion that a spread footing foundation system may be used for support of the proposed structure. The footings should be placed on undisturbed soils and/or engineered fill material. Potentially expansive soils will require particular attention in the design and construction. Lamar Valley Craftsman 637 Cowan Street Northern Colorado Gleotech Project No. 012-03 PROPOSED CONSTRUCTION' It is our understanding that a single-family residence will be built at the site. The residence will have a full -depth basement SITE EXPLORATION A total of two test borings were drilled on January 21, 2003. The borings were drilled to approximate depths of 15 feet at the locations shown on the Site Plan, Figure 1. The borings were advanced with a truck -mounted drilling rig, utilizing flinch diameter solid stem augers. The borings were located in the field by pacing from property lines and/or existing site features. Relative surface elevations at the boring locations were obtained by measurements with an engineer's level from a temporary bench mark (TBM) shown on the Site Plan. The accuracy of boring locations and elevations should only be assumed to the level implied by the methods used to determine each. Liithologic logs of each boring were •recorded by an engineering geologist during the drilling operations. At selected intervals, samples of the subsurface materials were taken by driving split - spoon and/or ring samplers. Standard penetration measurements were recorded while driving a split -spoon and/or ring sampler into the subsurface materials. The standard penetration test is a useful index in estimating the density of the materials encountered. Groundwater conditions were evaluated in each boring at the time of subsurface exploration, and two days after the drilling. Laboratory Testing The samples retrieved during the subsurface exploration were returned to our laboratory for observation by the project manager. The soils were classified in general accordance with the Unified Soil Classification System. At that time, the field descriptions were confirmed or modified and an applicable laboratory testing program was formulated. Boring logs were prepared and are attached with this report Laboratory tests were conducted on selected samples and are presented on the boring logs and attached laboratory test sheets. The test results were used for the geotechnical engineering analyses, and the development of foundation and earthwork recommendations. Selected samples were tested for the following engineering properties: 2 GEOTECHNICAL ENGINEERING REPORT PROPOSED RESIDENCE 637 COWAN STREET FORT COLLINS, COLORADO NORTHERN COLORADO GEOTECH PROJECT NO.012-03 FEBRUARY 13, 2003 SCOPE This report contains the results of our geotechnical engineering exploration for the proposed residence to be located at 637 Cowan Street in Fort Collins, Colorado. This report includes descriptions of, and geotechnical engineering recommendations relative to: • subsurface soil and bedrock conditions • groundwater conditions • foundation design and construction • basement construction • drainage • floor slab design and construction • earthwork The recommendations contained in this report are based upon the results of field and laboratory testing, engineering analyses, and experience with similar soil conditions, structures and our understanding of the proposed project. SITE CONDITIONS The proposed residence will be located on a "new" lot that will be created by splitting an existing lot into two parcels. The existing lot has a residence located on the north side of the lot The proposed residence will be located on the south side of the existing lot A small shed is located on the southwest comer of the lot Cowan street is located east of the site. An alley is located to the west A wooden fence and residence border the property to the south. TABLE OF CONTENTS Page No. Letterof Transmittal.............................................................................................................. ii SCOPE .............. SITE CONDITIONS .......................................... .....................................................................1 ...................................................1 PROPOSED CONSTRUCTION...........................................................................................2 x SITEEXPLORATION...........................................................................................................2 LaboratoryTesting......................................................................................................2 SUBSURFACECONDITIONS......:........................................................................................3 SoilConditions............................................................................................................3 Groundwater Conditions..............................................................................................3 FieldTest Results............................................................................................:...........3 Laboratory Test Results.............................................................................................. 3 DESIGN RECOMMENDATIONS.......................:...................................................................3 FoundationDesign...................................................................................................... 3 FootingFoundations.....................................................................:..................:...........4 BelowGrade Construction...........................................................................................4 SurfaceDrainage............................................................................................:........... 5 Floor Slab Design and Construction............................................................................5 General Earthwork..........................................................................................:...........6 SitePreparation................................................................................................7 Fill Materials and Placement..................................................................:...........7 GENERALCOMMENTS.......................................................................................................8 ATTACHMENTS Boring Location Plan Logs of Borings Laboratory Test Results February 13, 2003 Lamar Valley Craftsman PO Box 270887 Fort Collins, Colorado 80527 Attn: Mr. Barry Schram Re: Geotechnical Engineering Report 637 Cowan Street Fort Collins, Colorado Northem Colorado Geotech Project No. 012-03 Northam Colorado Geotech 2956 29th Street, Unit 21 Greeley, Colorado 80631 Phone: (970) 506-92" Fax: (970) 506-9242 Northern Colorado Geotech has completed a geotechnical engineering exploration for the proposed residence to be located at 637 Cowan Street in Fort Collins, Colorado The subsurface soils at the site consisted of lean day with sand that are underlain by silty sand with gravel at an approximate depth of 12 feet The results of our field exploration and laboratory testing indicate that the soils and bedrock at the site have low expansive potential and low to moderate load bearing capabilities. Based on the anticipated construction and the results of our engineering exploration, it is our opinion that the proposed residence may be supported on a spread footing foundation system. Slab on grade may be utilized for the interior floor system provided that care is taken in the placement and compaction of the subgrade soil. If you have any questions concerning this report or any of our consulting services, please do not hesitate to contact us. Sincerely, NORTHERN COLORADO GEOTECH Prepa by. Doug Leafgren, P.G. President \ Reviewed by: Gary G. Weeks, P.E. Vice President Copies to: Addressee (3) GEOTECHNICAL ENGINEERING REPORT PROPOSED RESIDENCE 637 COWAN STREET FORT COLLINS, COLORADO NORTHERN COLORADO GEOTECH PROJECT NO.012-03 February 13, 2003 Prepared for. Lamar Valley Craftsman PO Box 270887 Fort Collins, Colorado 80527 Attn: Mr. Barry Schram Northern Colorado Geotech 2956 29th Street, Unit 21 Greeley, Colorado 80631 Phone: (970) 506-9244 Fax: (970) 506-9242